Japanese police say they have added another name to a list of Japanese people allegedly abducted by North Korea. The woman disappeared while studying in Europe nearly 20 years ago.

Authorities in Japan say they are now investigating the disappearance of Keiko Arimoto. On Tuesday they said she may have been kidnapped by Pyongyang.

Ms. Arimoto was a resident of the Japanese city of Kobe, and went to study in London in the early 1980s. Her family last heard from her in August 1983, when the 23-year-old wrote from Copenhagen to say her return to Japan might be delayed.

Recently, a woman reportedly told police that she was involved in Ms. Arimoto's abduction. The woman, a Japanese national, is the former wife of a hijacker who helped commandeer a Japan Airlines jet to North Korea in 1970.

National Public Safety Commissioner Jin Murai, who oversees police operations, told reporters that "authorities will investigate the Arimoto case thoroughly."

Aside from Ms. Arimoto, Tokyo says that North Korean agents kidnapped at least 10 Japanese nationals from 1977 to 1980. North Korea denies the allegations. In the past, Pyongyang has promised to investigate cases of what it calls missing persons. But North Korea's Red Cross Society said in December that it had suspended its probe.

Japanese Foreign Minister Yoriko Kawaguchi says that "Japan will continue to seek the return of Mr. Arimoto and the other Japanese it thinks were abducted."

Tokyo says the victims were taken so that North Koreans could learn about Japan. The two nations have never had official diplomatic relations and tensions between them are high because of the alleged abductions and other issues.